The developmental etiology and pathogenesis of Hirschsprung disease

Primary Cilia Structure Is Prolonged in Enteric Neurons of 5xFAD Alzheimer's Disease Model Mice

Neurodegenerative diseases such as Alzheimer’s disease (AD) have long been acknowledged as mere disorders of the central nervous system (CNS). However, in recent years the gut with its autonomous nervous system and the multitude of microbial commensals has come into focus. Changes in gut properties have been described in patients and animal disease models such as altered enzyme secretion or architecture of the enteric nervous system. The underlying cellular mechanisms have so far only been poorly investigated. An important organelle for integrating potentially toxic signals such as the AD characteristic A-beta peptide is the primary cilium. This microtubule-based signaling organelle regulates numerous cellular processes. Even though the role of primary cilia in a variety of developmental and disease processes has recently been recognized, the contribution of defective ciliary signaling to neurodegenerative diseases such as AD, however, has not been investigated in detail so far. The AD mouse model 5xFAD was used to analyze possible changes in gut functionality by organ bath measurement of peristalsis movement. Subsequently, we cultured primary enteric neurons from mutant mice and wild type littermate controls and assessed for cellular pathomechanisms. Neurite mass was quantified within transwell culturing experiments. Using a combination of different markers for the primary cilium, cilia number and length were determined using fluorescence microscopy. 5xFAD mice showed altered gut anatomy, motility, and neurite mass of enteric neurons. Moreover, primary cilia could be demonstrated on the surface of enteric neurons and exhibited an elongated phenotype in 5xFAD mice. In parallel, we observed reduced β-Catenin expression, a key signaling molecule that regulates Wnt signaling, which is regulated in part via ciliary associated mechanisms. Both results could be recapitulated via in vitro treatments of enteric neurons from wild type mice with A-beta. So far, only a few reports on the probable role of primary cilia in AD can be found. Here, we reveal for the first time an architectural altered phenotype of primary cilia in the enteric nervous system of AD model mice, elicited potentially by neurotoxic A-beta. Potential changes on the sub-organelle level—also in CNS-derived neurons—require further investigations.

Clinical Efficacy of an Indwelling Transanal Tube for the Prevention of Anastomotic Leakage After Hirschsprung's Disease: A Single Center Experience with Chinese Patients

Background: The aim of this study was to investigate the clinical effectiveness of an indwelling transanal tube for the prevention of anastomotic leakage (AL) after a radical operation for Hirschsprung's disease (HD). Methods: We retrospectively analyzed the clinical data from 158 patients who had undergone laparoscopic-assisted Soave procedures for HD at our hospital from May 2015 to May 2019. Patients were divided into two groups depending upon whether the anal drainage tube was retained or not retained: an indwelling group (group A, n = 86) and a no-indwelling group (group B, n = 72). Results: All 158 children had a successful operation by a laparoscopic technique. There was no significant difference in the duration of the operation, the length of the incision, the amount of bleeding, or the postoperative hospitalization time between the two groups. Compared with the no-indwelling group, maintaining the transanal tube had significant advantages for preventing incidences of AL (P < .05). The 4-year follow-up showed that the incidence of postoperative enterocolitis with the indwelling transanal tube was significantly lower than in the group without the drainage tube (P < .05). Conclusions: The laparoscopic-assisted Soave procedure with an indwelling transanal tube is a safe and feasible method for the treatment of HD in children. This method can not only drain intestinal contents but also reduce the occurrence of AL.

Associations of CYP2B6 genetic polymorphisms with Hirschsprung's disease in a southern Chinese population

Background

Hirschsprung’s disease (HSCR) is an enteric nervous system birth defect partially caused by a genetic disorder. Single‐nucleotide polymorphisms (SNPs) of the cytochrome P450 family 2 subfamily B member 6 (CYP2B6) gene are reported to be associated with HSCR.

Methods

We evaluated the association of rs2054675, rs707265, and rs1042389 with HSCR susceptibility in southern Chinese children including 1470 HSCR patients and 1473 controls using the TaqMan SNP Genotyping Assay.

Results

rs2054675 C allele and the rs707265 G allele were risk SNPs for total colonic aganglionosis (OR = 1.82, 95% CI 1.29 ~ 2.55, P_adj < 0.001 and OR = 0.68, 95% CI 0.48 ~ 0.97, P_adj = 0.034). These results suggested that CYP2B6 rs2054675 and rs707265 polymorphisms were associated with increased susceptibility to the severe HSCR subtype in southern Chinese children.

Conclusion

We suggest that CYP2B6 rs2054675 and rs707265 polymorphisms are associated with increased susceptibility to the severe HSCR subtype in southern Chinese children.

Evaluation and Management of Persistent Problems After Surgery for Hirschsprung Disease in a Child

PURPOSE OF REVIEW

Ideally, after operative intervention, a child born with Hirschsprung disease (HD) should thrive, achieve fecal continence, and avoid recurrent episodes of abdominal distention and enterocolitis. However, a significant number of patients continue to struggle following their pull-through procedure. The purpose of this review is to present an organized and practical approach to the evaluation and management of the symptomatic patient post pull-through operation for HD.

RECENT FINDINGS

Children diagnosed with HD who are not doing well after their initial operation can be categorized in three distinct groups: (1) those that have fecal incontinence, (2) those with obstructive symptoms, and (3) those with recurrent episodes of enterocolitis. It is important to have a systematic diagnostic approach for these patients based on a comprehensive protocol. All three of these patient groups can be treated with a combination of either medical management, reoperation when a specific anatomic or pathologic etiology is identified, or botulinum toxin for non-relaxing sphincters contributing to the obstructive symptoms or recurrent enterocolitis. For patients not doing well after their initial pull-through, a systematic workup should be employed to determine the etiology. Once identified, a multidisciplinary and organized approach to management of the symptomatic patients can alleviate most post pull-through symptoms.

Association between ABHD1 and DOK6 polymorphisms and susceptibility to Hirschsprung disease in Southern Chinese children

Hirschsprung disease (HSCR) is an infrequent congenital intestinal dysplasia. The known genetic variations are unable to fully explain the pathogenesis of HSCR. The α/β‐hydratase domain 1 (ABHD1) interferes with the proliferation and migration of intestinal stem cells. Docking protein 6 (DOK6) is involved in neurodevelopment through RET signalling pathway. We examined the association of ABHD1 and DOK6 genetic variants with HSCR using 1470 controls and 1473 HSCR patients from Southern Chinese children. The results clarified that DOK6 rs12968648 G allele significantly increased HSCR susceptibility, in the allelic model (p = 0.034; OR = 1.12, 95%CI = 1.01~1.24) and the dominant model (p = 0.038; OR = 1.12, 95%CI = 1.01~1.25). Clinical stratification analysis showed that rs12968648 G allele was associated with increased risk of short‐segment HSCR (S‐HSCR), in the allelic model (p = 0.028; OR = 1.14, 95%CI = 1.01~1.28) and the additive model (p = 0.030; OR = 1.14, 95%CI = 1.01~1.28). ABHD1 rs2304678 C allele had higher risk to develop total colonic aganglionosis (TCA) in the allelic model (p = 7.04E‐03; OR = 1.67, 95%CI = 1.15~2.43) and the dominant model (p = 4.12E‐03; OR = 1.93, 95%CI = 1.23~3.04). DOK6 rs12968648 and ABHD1 rs2304678 had significant intergenic synergistic effect according to logical regression (p = 0.0081; OR = 0.76, 95%CI = 0.63~0.93) and multifactor dimensionality reduction (MDR, p = 0.0045; OR = 1.25, 95%CI = 1.07~1.46). This study verified two susceptible variations of HSCR on ABHD1 and DOK6. Their roles in HSCR should be conducted in further studies.

Hirschsprung disease and Paediatric Intestinal Pseudo-obstruction

Hirschsprung disease (HSCR) and Paediatric Intestinal Pseudo-obstruction (PIPO) comprise two of the most recognized and severe disorders of gastrointestinal (GI) motility. HSCR is a developmental disorder of the enteric nervous system invariably affecting the large intestine, whereas the majority of PIPO conditions represent congenital disorders of one or more components of the neuromusculature and more diffusely affect the GI tract. Histopathology is deemed the gold standard for the diagnosis of HSCR and, arguably, of PIPO, but, other diagnostic modalities such as manometric and genetic studies have seen recent advances that may increase their utility. Especially for PIPO, management is multidisciplinary and best performed in specialist referral centres. Surgery remains the only viable treatment for HSCR and appears essential to optimize and sustain feeding and viability of intestinal function in PIPO patients. Novel therapies such as neural stem cell transplants show promise for the future.

Urinary Incontinence Secondary to Fecal Impaction in a Patient With Likely Undiagnosed Hirschsprung's Disease

Hirschsprung's disease is caused by the failure of migration of neural crest cells to the hindgut, causing a lack of development of ganglion cells in the submucosal and myenteric plexuses of the colonic wall. Hirschsprung's disease most often presents in infants with failure to pass meconium in the first two days of life. We present the case of an eight-year-old male with chronic constipation since birth who presented to the emergency department with signs concerning spinal cord compression. To our knowledge, this is the first of such a case presenting with urinary incontinence.

Factors Affecting Higher Readmission Rates and Costs in Pediatric Patients With Hirschsprung Disease

BACKGROUND

Hirschsprung disease is a relatively uncommon disorder of the developing gastrointestinal tract that requires surgical intervention to restore long-term function. While readmission for Hirschsprung-related complications is a known concern in these patients, we sought to identify patient-level factors associated with a prolonged hospital stay, increased costs at the time of a pull-through operation, as well as the risk for all-cause inpatient readmission after surgery. We hypothesized that higher level of care requirement during the operative stay, age at operation, and length of stay (LOS) would portend increased readmissions and disease-related complications such as Hirschsprung-associated enterocolitis.

METHODS

Data was obtained from the Pediatric Health Information System database on all Hirschprung patients who underwent a pull-through operation between 2004 and 2019. Regression analyses were performed on this cohort of 3345 patients. Multivariable regression models were utilized to analyze the key outcome variables of postoperative LOS and adjusted charges.

RESULTS

Post-operative LOS was significantly increased by the presence of a surgical complication, congenital/genetic defect, or neurologic/neuromuscular defect. Increased LOS was also seen in Black patients. The cost of pull-through operations was significantly higher in patients admitted to the NICU and ICU during index hospitalization, with a cost increase of approximately $75,000 and $57,000 respectively. Presence of a surgical complication, comorbid congenital/genetic defect, and need for mechanical ventilation were associated with higher odds of inpatient readmission.

CONCLUSION

The management of patients with Hirschsprung disease is longitudinal and complex. Identification of key patient metrics can aid clinicians in developing targeted care and education strategies to minimize readmission and excessive hospital charges.

The Emerging Genetic Landscape of Hirschsprung Disease and Its Potential Clinical Applications

Hirschsprung disease (HSCR) is the leading cause of neonatal functional intestinal obstruction. It is a rare congenital disease with an incidence of one in 3,500-5,000 live births. HSCR is characterized by the absence of enteric ganglia in the distal colon, plausibly due to genetic defects perturbing the normal migration, proliferation, differentiation, and/or survival of the enteric neural crest cells as well as impaired interaction with the enteric progenitor cell niche. Early linkage analyses in Mendelian and syndromic forms of HSCR uncovered variants with large effects in major HSCR genes including RET, EDNRB, and their interacting partners in the same biological pathways. With the advances in genome-wide genotyping and next-generation sequencing technologies, there has been a remarkable progress in understanding of the genetic basis of HSCR in the past few years, with common and rare variants with small to moderate effects being uncovered. The discovery of new HSCR genes such as neuregulin and BACE2 as well as the deeper understanding of the roles and mechanisms of known HSCR genes provided solid evidence that many HSCR cases are in the form of complex polygenic/oligogenic disorder where rare variants act in the sensitized background of HSCR-associated common variants. This review summarizes the roadmap of genetic discoveries of HSCR from the earlier family-based linkage analyses to the recent population-based genome-wide analyses coupled with functional genomics, and how these discoveries facilitated our understanding of the genetic architecture of this complex disease and provide the foundation of clinical translation for precision and stratified medicine.

Literature review: enteric nervous system development, genetic and epigenetic regulation in the etiology of Hirschsprung's disease

Hirschsprung's disease (HSCR) is a developmental disorder of the enteric nervous system (ENS) derived from neural crest cells (NCCs), which affects their migration, proliferation, differentiation, or preservation in the digestive tract, resulting in aganglionosis in the distal intestine. The regulation of both NCCs and the surrounding environment involves various genes, signaling pathways, transcription factors, and morphogens. Therefore, changes in gene expression during the development of the ENS may contribute to the pathogenesis of HSCR.

This review discusses several mechanisms involved in the development of ENS, confirming that deviant genetic and epigenetic patterns, such as DNA methylation, histone modification, and microRNA (miRNA) regulation, can contribute to the development of neurocristopathy. Specifically, the epigenetic regulation of miRNA expression and its relationship to cellular interactions and gene activation through various major pathways in Hirschsprung's disease will be discussed.

How Smooth Muscle Contractions Shape the Developing Enteric Nervous System

Neurons and glia of the enteric nervous system (ENS) are constantly subject to mechanical stress stemming from contractions of the gut wall or pressure of the bolus, both in adulthood and during embryonic development. Because it is known that mechanical forces can have long reaching effects on neural growth, we investigate here how contractions of the circular smooth muscle of the gut impact morphogenesis of the developing fetal ENS, in chicken and mouse embryos. We find that the number of enteric ganglia is fixed early in development and that subsequent ENS morphogenesis consists in the anisotropic expansion of a hexagonal honeycomb (chicken) or a square (mouse) lattice, without de-novo ganglion formation. We image the deformations of the ENS during spontaneous myogenic motility and show that circular smooth muscle contractile waves induce longitudinal strain on the ENS network; we rationalize this behavior by mechanical finite element modeling of the incompressible gut wall. We find that the longitudinal anisotropy of the ENS vanishes when contractile waves are suppressed in organ culture, showing that these contractile forces play a key role in sculpting the developing ENS. We conclude by summarizing different key events in the fetal development of the ENS and the role played by mechanics in the morphogenesis of this unique nerve network.

Skip Segment Hirschsprung Disease Managed by Pull-Through of the Right Colon

Hirschsprung disease is the most common neurocristopathy in children, resulting in the congenital loss of enteric ganglia. Rare reports of skip lesions have previously been reported in the literature. We present a case of skip lesions known prior to surgery and managed by pull-through of the right colon that allowed the preservation of the colon.

Hirschsprung disease and other gastrointestinal motility disorders in patients with CCHS

Congenital central hypoventilation syndrome (CCHS) is an autonomic nervous system dysfunction due to PHOX2B gene mutation. Little is known about gastrointestinal motility disorders in CCHS patients. This study aims to describe the spectrum of gastrointestinal motility disorders in CCHS and provide PHOX2B genotype-phenotype correlation with Hirschsprung Disease (HD). We reviewed the records of 72 CCHS patients seen at Children's Hospital Los Angeles from 1999 to 2019. Data collected included demographics, PHOX2B genotype, ventilator dependence, medical and surgical history, and gastrointestinal motility studies. Of the 72 patients, 31% had HD, 50% females, and 60% had 20/27 PARM. Rectosigmoid HD formed 73% of the cases whereas long segment (up to splenic flexure involvement) forms represented 23%. Four patients had total colonic aganglionosis, including one patient with 20/25 PARM genotype. One HD patient was identified with colonic myopathy in the residual segment. One patient was found to have achalasia type 1.Conclusion: Nearly one third of our CCHS patients had HD. Although most had 20/27 PARM, 2 patients had 20/25 PARM. Thus, CCHS patients with constipation are at risk for HD regardless of genotype. Colonic myopathy may coexist in treated HD with refractory constipation. Achalasia may occur in patients with CCHS. What is Known: • Patients with CCHS have motility disorders and present with esophageal dysmotility and constipation as a manifestation of their autonomic nervous system dysfunction. • About 20% of patients with CCHS have Hirschsprung disease and previously described to be associated with NPARM and 20/27 PARM genotype. What is New: • Thirty-one percent of CCHS patients in our series have Hirschsprung disease (HD). • HD, including the more severe total colonic aganglionosis was found in a patient with 20/25 PARM genotype suggesting that CCHS patients with constipation should be screened for HD regardless of genotype.

Associations between common genetic variants in microRNAs and Hirschsprung disease susceptibility in Southern Chinese children

Introduction

Hirschsprung disease (HSCR), characterized by the defective migration of enteric neural crest cells, is a severe congenital tract disease in infants. Its etiology is not clear at present, although a genetic component plays an important role in its etiology. Many studies focused on the polymorphisms of microRNA (miRNA) in several disease progressions have been reported, including HSCR. However, the findings remain inconclusive. The present study aimed to explore the association of genetic variants in miRNAs and HSCR susceptibility in Southern Chinese children.

Methods

Five single nucleotide polymorphisms (SNPs) (miR‐146A rs2910164, miR‐4318 rs8096901, miR‐3142 rs2431697, miR‐3142 rs2431097 and miR‐3142 rs5705329) were included to be genotyped in the stratified analysis through the Mass ARRAY iPLEX Gold system (Sequenom, San Diego, CA, USA) conducted on all the samples, comprising 1470 cases and 1473 controls. After quality control, the minor allele frequency was compared in cases and controls to analyze the association between SNPs and HSCR using PLINK 1.9 (https://www.cog‐genomics.org/plink) and multiple heritability models were tested (additive, recessive and dominant models).

Results

Our results indicated that miR‐4318 rs8096901 polymorphisms were associated with HSCR susceptibility in Southern Chinese children, especially in short‐segment HSCR (S‐HSCR) patients after stratified analysis.

Conclusions

In summary, we report that miR‐4318 rs8096901 was associated with HSCR, especially in SHSCR patients.

Quantitative Proteomics Reveals Association of Neuron Projection Development Genes ARF4, KIF5B, and RAB8A With Hirschsprung Disease

Hirschsprung disease (HSCR) is a heterogeneous group of neurocristopathy characterized by the absence of the enteric ganglia along a variable length of the intestine. Genetic defects play a major role in the pathogenesis of HSCR, whereas family studies of pathogenic variants in all the known genes (loci) only demonstrate incomplete penetrance and variable expressivity for unknown reasons. Here, we applied large-scale, quantitative proteomics of human colon tissues from 21 patients using isobaric tags for relative and absolute quantification. method followed by bioinformatics analysis. Selected findings were confirmed by parallel reaction monitoring verification. At last, the interesting differentially expressed proteins were confirmed by Western blot. A total of 5341 proteins in human colon tissues were identified. Among them, 664 proteins with >1.2-fold difference were identified in six groups: groups A1 and A2 pooled protein from the ganglionic and aganglionic colon of male, long-segment HSCR patients (n = 7); groups B1 and B2 pooled protein from the ganglionic and aganglionic colon of male, short-segment HSCR patients (n = 7); and groups C1 and C2 pooled protein from the ganglionic and aganglionic colon of female, short-segment HSCR patients (n = 7). Based on these analyses, 49 proteins from five pathways were selected for parallel reaction monitoring verification, including ribosome, endocytosis, spliceosome, oxidative phosphorylation, and cell adhesion. The downregulation of three neuron projection development genes ARF4, KIF5B, and RAB8A in the aganglionic part of the colon was verified in 15 paired colon samples using Western blot. The findings of this study will shed new light on the pathogenesis of HSCR and facilitate the development of therapeutic targets.

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Large-scale, quantitative proteomics of human colon tissues from Hirschsprung disease patients.

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Parallel reaction monitoring, Western blotting, and immunohistochemical staining for validation.

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Four pathways related to differentially expressed proteins: ribosome, endocytosis, spliceosome, and axon guidance.

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Downregulation of ARF4, KIF5B, and RAB8A in the aganglionic (stenotic) colon segment.

Not Just for Urine: A Versatile Tool for Foreign Body Removal

The swallowed or aspirated foreign body is a common pediatric emergency medicine complaint for which emergency providers must be familiar with the intricacies of management. Most swallowed foreign bodies will harmlessly pass through the GI tract, but children with GI tract abnormalities may have an increased risk of object impaction. There are few reported cases of foreign object ingestion in children with GI tract abnormalities, specifically ostomies. The Foley catheter is a versatile tool that is easily accessible in the ED setting. We present a novel case of foreign body ingestion in an infant with a colostomy secondary to Hirschsprung's disease managed with Foley catheter retrieval through an ileostomy stoma. A 17-month-old infant presented to the ED with a chief complaint of an episode of bloody vomiting. He had a two-day history of increased irritability and intolerance of feeds with emesis after every feed. The child's medical history is pertinent for Hirschsprung's disease, for which the patient had a pull-through procedure shortly after birth and a revision of the pull-through. On physical examination, the patient's ostomy was found to contain brown-green liquid stool. A small ovular mass was visualized at the stoma during crying episodes. Supine posteroanterior radiograph of the abdomen showed an oval-shaped radiolucency consistent with a metallic ingested foreign body at the site of the stoma. The foreign object was removed using a Foley catheter and forceps and was found to be a penny. The patient was observed and discharged without complications later that day. Treatment of a symptomatic ingested foreign object requires careful consideration of the type of object present and its location in the body. In this case report, we discussed the removal of an ingested coin in a symptomatic 17-month-old infant with a history of ileostomy secondary to Hirschsprung's disease using a Foley catheter. In children with ostomies, prompt imaging and non-surgical removal may be an option to manage retrieval of these objects if the patient is stable and symptoms are not severe.

Significant Association of rs2147555 Genetic Polymorphism in the EDNRB Gene with Hirschsprung Disease in Southern Chinese Children

Hirschsprung disease (HSCR) is a human birth defect at the clinical setting, usually characterized by an absent enteric nervous system (ENS) from the distal bowel. The majority of HSCR cases represent a complex disorder resulting from the interaction of multiple genetic and environmental factors. Genetic events have been described to be involved in the abnormal development of the enteric nervous system. Although variants in several genes like RET and EDNRB have been suggested to contribute major risks to HSCR, very little is known about their involvement in the onset of HSCR. Here, we studied a large Chinese Han cohort consisting of 1,470 HSCR patients and 1,473 non-HSCR controls to further test whether there are more variants in EDNRB associated with HSCR. Our results provided the first evidence that rs2147555 in EDNRB confers a significant risk of HSCR in a Chinese Han population for both allelic frequencies (P = 4.16 × 10⁻³; OR = 1.29) and genotypic frequencies assuming either a dominant or recessive model (P = 0.011 and P = 0.027, respectively). When different subtypes of HSCR cases were analyzed, the association remained significant (OR = 1.33, P = 0.003 for short-segment HSCR; OR = 1.34, P = 0.044 for long segment HSCR).

Hirschsprung's Disease-Recent Understanding of Embryonic Aspects, Etiopathogenesis and Future Treatment Avenues

Hirschsprung's disease is a neurocristopathy, caused by defective migration, proliferation, differentiation and survival of neural crest cells, leading to gut aganglionosis. It usually manifests rapidly after birth, affecting 1 in 5000 live births around the globe. In recent decades, there has been a significant improvement in the understanding of its genetics and the association with other congenital anomalies, which share the pathomechanism of improper development of the neural crest. Apart from that, several cell populations which do not originate from the neural crest, but contribute to the development of Hirschsprung's disease, have also been described, namely mast cells and interstitial cells of Cajal. From the diagnostic perspective, researchers also focused on "Variants of Hirschsprung's disease", which can mimic the clinical signs of the disease, but are in fact different entities, with distinct prognosis and treatment approaches. The treatment of Hirschsprung's disease is usually surgical resection of the aganglionic part of the intestine, however, as many as 30-50% of patients experience persisting symptoms. Considering this fact, this review article also outlines future hopes and perspectives in Hirschsprung's disease management, which has the potential to benefit from the advancements in the fields of cell-based therapy and tissue engineering.

From head to tail: regionalization of the neural crest

The neural crest is regionalized along the anteroposterior axis, as demonstrated by foundational lineage-tracing experiments that showed the restricted developmental potential of neural crest cells originating in the head. Here, we explore how recent studies of experimental embryology, genetic circuits and stem cell differentiation have shaped our understanding of the mechanisms that establish axial-specific populations of neural crest cells. Additionally, we evaluate how comparative, anatomical and genomic approaches have informed our current understanding of the evolution of the neural crest and its contribution to the vertebrate body.

Ultrashort-segment Hirschsprung disease in a 4-year-old female

Hirschsprung disease (HSCR) is characterized by the absence of neuronal ganglion cells in a distal portion of the intestinal tract [1]. In 1691, Frederick Ruysch described the disease as congenital megacolon. HSCR-associated congenital anomalies have been reported in 5–32% of affected patients [2]. The clinical symptoms of HSCR are usually evident in the neonatal period. However, in some cases where the extent of the aganglionic segment is short, symptoms may become clinically relevant later in childhood [3]. HSCR is one of the most difficult diseases to identify in pediatric surgery due to its multiple clinical, histological and radiological variations [2, 3]. The goal of surgical management is to remove the aganglionic segment and reconstruct the intestinal tract through techniques such as Swenson, Duhamel and Soave [4]. The following case consists of a 4-year-old patient with a chronic presentation of constipation secondary to ultrashort-segment Hirschsprung disease.

Association between miR-492 rs2289030 G>C and susceptibility to Hirschsprung disease in southern Chinese children

OBJECTIVE

Hirschsprung disease (HSCR) originates from disruption of normal neural crest cell migration, differentiation, and proliferation during the fifth to eighth weeks of gestation. This results in the absence of intestinal ganglion cells in the distal intestinal tract. However, genetic variations affecting embryonic development of intestinal ganglion cells are unclear. Therefore, this study aimed to investigated the potential value of miR-492 rs2289030 G>C as a marker of susceptibility to HSCR.

METHODS

In this case-control study in southern Chinese children, we collected samples from 1473 controls and 1470 patients with HSCR. TaqMan genotyping of miR-492 rs2289030 G>C was performed by real-time fluorescent quantitative polymerase chain reaction.

RESULTS

Multivariate logistic regression analysis showed that there was no significant association between the presence of the miR-492 rs2289030 G>C polymorphism and susceptibility to HSCR by evaluating the values of pooled odds ratios and 95% confidence intervals. Similarly, among different HSCR subtypes, rs2289030 G>C was also not associated with HSCR in hierarchical analysis.

CONCLUSIONS

Our results suggest that the miR-492 rs2289030 G>C polymorphism is not associated with susceptibility to HSCR in southern Chinese children. These results need to be further confirmed by investigating a more diverse ethnic population of patients with HSCR.

miR-618 rs2682818 C>A polymorphism decreases Hirschsprung disease risk in Chinese children

MicroRNAs (miRNAs) are endogenous non-coding small RNAs that play an important role in the development of many malignant tumors. In addition, recent studies have reported that single nucleotide polymorphisms (SNPs) located in the miRNA functional region was inextricably linked to tumor susceptibility. In the present study, we investigated the susceptibility between miR-618 rs2682818 C>A and Hirschsprung disease (HSCR) in the Southern Chinese population (1470 patients and 1473 controls). Odds ratios (ORs) and 95% confidence intervals (CIs) were used for estimating the strength of interrelation between them. We found that the CA/AA genotypes of miR-618 rs2682818 were associated with a decreased risk of HSCR when compared with the CC genotype (OR = 0.84, 95% CI = 0.72–0.99, P=0.032). Based on the stratified analysis of HSCR subtypes, the rs2682818 CA/AA genotypes were able to significantly lessen the risk of HSCR compared with CC genotype in patients with long-segment HSCR (adjusted OR = 0.70, 95% CI = 0.52–0.93, P=0.013). In conclusion, our results indicated that the miR-618 rs2682818 C>A polymorphism was associated with a reduced risk of HSCR in Chinese children, especially in patients with long-segment HSCR (L-HSCR) subtype.

Negative Association Between lncRNA HOTTIP rs3807598 C>G and Hirschsprung Disease

Background

Hirschsprung disease (HSCR) is a congenital disease that arises from defective intestinal neural system. LncRNA HOTTIP is a critical gene in various diseases, including HSCR. No epidemiological studies have explored the correlation between lncRNA HOTTIP single nucleotide polymorphisms (SNPs) and HSCR risk. We here lead as a pioneer to explore whether SNPs in lncRNA HOTTIP impact the risk of HSCR and HSCR subtypes in an unrelated Chinese population.

Methods

We used the TaqMan method to genotype rs3807598 C>G of the lncRNA HOTTIP gene using 1470 HSCR cases and 1473 healthy controls. Of them, 1441 cases and 1434 controls were successfully genotyped. We adopted odds ratios (ORs) and 95% confidence intervals (CIs) to quantify the relationship.

Results

We got an unexpected outcome that lncRNA HOTTIP SNP rs3807598 C>G could not modify the risk of HSCR (CG vs. CC: adjusted OR=0.89, 95% CI=0.74–1.07; GG vs. CC: adjusted OR=1.10, 95% CI=0.89–1.37; GG/CG vs CC: adjusted OR=0.95, 95% CI=0.80–1.13; and GG vs. CC/CG: adjusted OR=1.19, 95% CI=0.99–1.43). What’s more, risk effect of lncRNA HOTTIP rs3807598 C>G is still not obvious in stratification analysis by HSCR subtype.

Conclusion

Our studies did not provide statistical evidence of a correlation between lncRNA HOTTIP SNP rs3807598 C>G and susceptibility of HSCR in the Chinese population that is being studied. Further validation study with a larger sample size covering multi-ethnic groups is warranted.

Primary laparoscopic endorectal pull-through procedure with or without a postoperative rectal tube for hirschsprung disease: a multicenter perspective study

BACKGROUND

Hirschsprung-associated enterocolitis (HAEC) is a significant complication of HD both in the pre- and postoperative periods. This was a large multicenter series study to determine the effect of preserving a postoperative rectal tube on preventing HAEC after primary laparoscopic endorectal pull-through procedure.

METHODS

Between 2014 and 2017, a total of 383 consecutive patients with rectosigmoid segment HD were randomly divided into group A (n = 190) and group B (n = 193). All of them underwent primary laparoscopic pull-through procedure, with the same postoperative treatment protocols except for group A with a rectal tube after surgery for 5 days, while group B did not have it. The mean time of follow-up was 2.0 ± 0.53 years (0.5-3.6 years). Demographics, operative data, postoperative complications, and clinical outcomes were compared between these two groups.

RESULTS

Outcomes within 1 month after surgery indicated a lower incidence of abdominal distention (4% vs 15.5%, P < 0.05) and postoperative HAEC (1.2% vs 6.8%, P < 0.05) in group A compared to group B. Beyond 1 month after surgery, the overall incidence of HAEC was not significantly different (12% vs 13.1%, P = 0.54). However, further analysis revealed that the patients who suffered HAEC twice or above twice in group A were significantly less than those in group B (3.6% vs 8.3%, p = 0.02). There were no significant differences in the defecation frequency and other complications.

CONCLUSIONS

Primary laparoscopic endorectal pull-through procedure with a postoperative rectal tube can reduce the early-stage postoperative incidence of abdominal distension and HAEC and the risk of HAEC recurrence in the long term, and is beneficial to postoperative management.

LEVEL OF EVIDENCE

Level 2.

The enteric nervous system: “A little brain in the gut”

The gut’s own autonomous nervous system, the enteric nervous system (ENS), has fascinated scientists for more than 100 years. It functions, in the true sense of the word, autonomously, by performing complex tasks and controlling vital functions independently of extrinsic inputs. At the same time, the ENS is bombarded with signals from other cells in the gut wall and lumen and has to integrate all of these inputs. We describe the main functions of the ENS under physiological conditions and give a few examples of its role in gut diseases. The ENS has received increasing attention recently as scientists outside the field of Neurogastroenterology realize its important role in the pathogenesis of Parkinson’s, autism and multiple sclerosis.

New mutations associated with Hirschsprung disease

INTRODUCTION

Hirschsprung Disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications.

MATERIAL AND METHODS

Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013.

RESULTS

We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene: Two of the mutations are novel and they have not been reported in the medical literature.

CONCLUSIONS

The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

[New mutations associated with Hirschsprung disease]

INTRODUCTION

Hirschsprung disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications.

MATERIAL AND METHODS

Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013.

RESULTS

We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene. Two of the mutations are novel and they have not been reported in the medical literature.

CONCLUSIONS

The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

Congenital hyperinsulinism associated with Hirschsprung's disease-a report of an extremely rare case

Background

Congenital hyperinsulinism (CH) is a rare disease, characterized by severe hypoglycemia induced by inappropriate insulin secretion from pancreatic beta-cells in neonate and infant. Hirschsprung’s disease (HD) is also a rare disease in which infants show severe bowel movement disorder. We herein report an extremely rare case of combined CH and HD.

Case presentation

The patient was a full-term male infant who showed poor feeding, vomiting, and hypotonia with lethargy on the day of birth. He was transferred to tertiary hospital after a laboratory analysis revealed hyperinsulinemic hypoglycemia. The patient showed remarkable abdominal distension without meconium defecation. An abdominal X-ray showed marked dilatation of the large bowel. He was diagnosed with CH (nesidioblastosis) associated with suspected HD. He was initially treated with an intravenous infusion of high-dose glucose with the intermittent injection of glucagon. This was successfully followed by treatment with diazoxide and octreotide (a somatostatin analog). At 8 months of age, HD was confirmed by the acetylcholinesterase staining of a rectal mucosal biopsy specimen, and a transanal pull-through operation was performed to treat HD. At 14 months of age, subtotal pancreatectomy was performed for the treatment of focal CH located in the pancreatic body. His postoperative course over the past 12 years has been uneventful without any neurologic or bowel movement disorders.

Conclusions

Although it is extremely rare for CH to be associated with HD, associated HD should be considered when a patient with CH presents severe constipation.

Are We Underdiagnosing Hirschsprung Disease?

Hirschsprung disease (HSCR) is conventionally defined as aganglionosis of the distal rectum and a variable length of proximal contiguous bowel with a transition zone of ganglionic, but neuroanatomically abnormal, bowel located immediately upstream. Recent improvement in our understanding of the pathology and genetics of HSCR and relevant animal models indicates highly variable expressivity. The spectrum of intestinal neuropathology includes patients with very short-segment aganglionosis, limited to the distal 1 to 2 cm of the rectum, and possibly patients with no true aganglionic segment, but nonphysiological transition zone pathology in their distal rectums. The presence or absence of submucosal ganglion cells in a rectal biopsy is not sufficient to exclude these patients, in whom submucosal nerve hypertrophy and/or abnormal cholinergic mucosal innervation may be the only diagnostic clues. In addition, diagnosis or exclusion of HSCR by rectal biopsy now relies in part on mucosal patterns of calretinin immunohistochemistry, with less emphasis on submucosal tissue adequacy and assessment of cholinergic innervation. These recent trends in the surgical pathology approach to rectal biopsies may miss patients at the phenotypically milder end of the malformation spectrum, with profound implications for subsequent management, prognosis, and genetic counseling.

ASSOCIATION OF RS2435357 AND RS1800858 POLYMORPHISMS IN RET PROTO-ONCOGENE WITH HIRSCHSPRUNG DISEASE: SYSTEMATIC REVIEW AND META-ANALYSIS

Introduction:

Many published studies have estimated the association of rs2435357 and rs1800858 polymorphisms in the proto-oncogene rearranged during transfection (RET) gene with Hirschsprung disease (HSCR) risk. However, the results remain inconsistent and controversial.

Aim:

To perform a meta-analysis get a more accurate estimation of the association of rs2435357 and rs1800858 polymorphisms in the RET proto-oncogene with HSCR risk.

Methods:

The eligible literatures were searched by PubMed, Google Scholar, EMBASE, and Chinese National Knowledge Infrastructure (CNKI) up to June 30, 2018. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the susceptibility to HSCR.

Results:

A total of 20 studies, including ten (1,136 cases 2,420 controls) for rs2435357 and ten (917 cases 1,159 controls) for rs1800858 were included. The overall results indicated that the rs2435357 (allele model: OR=0.230, 95% CI 0.178-0.298, p=0.001; homozygote model: OR=0.079, 95% CI 0.048-0.130, p=0.001; heterozygote model: OR=0.149, 95% CI 0.048-0.130, p=0.001; dominant model: OR=0.132, 95% CI 0.098-0.179, p=0.001; and recessive model: OR=0.239, 95% CI 0.161-0.353, p=0.001) and rs1800858 (allele model: OR=5.594, 95% CI 3.653-8.877, p=0.001; homozygote model: OR=8.453, 95% CI 3.783-18.890, p=0.001; dominant model: OR=3.469, 95% CI 1.881-6.396, p=0.001; and recessive model: OR=6.120, 95% CI 3.608-10.381, p=0.001) polymorphisms were associated with the increased risk of HSCR in overall.

Conclusions:

The results suggest that the rs2435357 and rs1800858 polymorphisms in the RET proto-oncogene might be associated with HSCR risk.

MPGES-1 derived PGE2 inhibits cell migration by regulating ARP2/3 in the pathogenesis of Hirschsprung disease

BACKGROUND

We previously studied the metabolomics, transcriptomics and proteomics of intestinal tissue of Hirschsprung disease (HSCR) patients; the results suggested that the expression of prostaglandin E2(PGE2), prostaglandin E receptor 2(PTGER2) and microsomal prostaglandin E synthase-1 (mPGES-1) notably increased in HSCR colon tissues. We already verified the differential expression of PGE2/EP2 in HSCR patients; therefore we investigate how mPGES-1 derived PGE2 affects the migration and the potential mechanism in cells, revealing the role of mPGES-1 derived PGE2 in the pathogenesis of Hirschsprung disease.

METHODS

SH-SY5Y and SK-N-BE2 cell lines were obtained from American Type Culture Collection (ATCC, USA). Prostaglandin E2 and its synthetase inhibitors were purchased from Med Chem Express (MCE, USA). Migration assays were performed with transwell and scratch assays. Cell proliferation was confirmed by CCK8 method. Flow cytometer was used to detect the cell cycle and cell apoptosis. The expressions of mRNA and protein of EP2, ARP2/3 were determined by qRT-PCR and western blot respectively. Immunofluorescence and confocal laser scanning microscopy were used to observe the morphology and function of cytoskeleton.

RESULTS

MPGES-1 derived PGE2 decreased the relative expression of EP2 and ARP2/3 and caused damage to cytoskeleton. As to cell functions, PGE2 inhibited cell migration while having no effects on the proliferation, cell cycle and apoptosis. By adding mPGES-1 inhibitor MK886 the abnormal expression and damaged cell function were reversed.

CONCLUSIONS

MPGES-1 derived PGE2 inhibits the cell migration by regulating ARP2/3 complex via prostaglandin E2 receptor. Potential mechanisms are the damage of cytoskeleton and related proteins leading to failure of cell polarize and migration. Here we thoroughly inquire the role mPGES-1 derived PGE2 plays in cell migration which might provide a new thinking in the investigation interrelated to the pathogenesis of HSCR.

Clinicopathological Characteristics of Hirschsprung's Disease With Emphasis on Diagnosis and Management: A Single-Center Study in the Kingdom of Saudi Arabia

Introduction: Hirschsprung’s Disease (HD) is a motor disorder of the gut caused by the failure of neural crest cells to migrate craniocaudally into the bowel during intestinal development, resulting in a functional obstruction. The majority of patients with HD are diagnosed in the neonatal period when they present with symptoms of distal intestinal obstruction. Aim: This study aims to identify the clinic-pathological characteristic of HD patients in our institution in KSA and comparing it with local and international data. Materials and Methods: This retrospective cohort study was conducted in King Abdulaziz Medical City (KAMC), a tertiary care center in Riyadh, Kingdome of Saudi Arabia (KSA). Results: A total of 54 patients (72% male) were diagnosed with HD. Forty-eight patients (89%) were born at term, and 6 were pre-term. Sixty-three percent of the patients presented in the neonatal period. Twenty-two patients (41%) underwent one-stage endorectal pull-through procedure, 23 patients (43%) two-stage endorectal pull-through, and 9 patients (16%) had three-stage endorectal pull-through. Five out of 54 patients had ganglion cells seen on FS but were absent in the permanent section. Therefore, the concordance rate was 90.8%. Conclusion: FS biopsy is a necessary method to determine the level of aganglionosis intraoperatively in HD, but the definitive diagnosis should be with permanent section. Also, the choice of surgical operation type (single-stage or multi-stage pull-through) depends on the patient’s clinical condition.

Results of rectoanal manometry after a novel laparoscopic technique: laparoscope-assisted heart-shaped anastomosis for Hirschsprung's disease

PURPOSE

The present research utilizes a mid-term follow-up study to assess the results of anorectal manometry after laparoscope-assisted heart-shaped anastomosis (LHSA) for Hirschsprung's disease (HSCR), and compares it to a more generally applied approach, the laparoscope-assisted Soave procedure (LSP).

METHODS

Retrospectively, patients from January 2015 to June 2017 who received LHSA or LSP were included in this study. After surgery, anorectal manometry was performed by the outpatient department. Anal sphincter resting pressure, anal canal length, amplitude of anal contraction, and frequency of anal contraction pre- and postoperatively were recorded. Additionally, mid-term complications were also monitored.

RESULTS

Preoperative manometry showed no statistically significant difference between the LHSA and LSP groups. Postoperatively, anal sphincter resting pressure was lower in the LHSA group (60.64 ± 9.33 vs. 68.84 ± 11.80 mmHg, p = 0.001). Furthermore, anal canal length of the LHSA group was shorter than that of the LSP group (1.41 ± 0.18 vs. 1.53 ± 0.25 cm, p = 0.015). Frequency of anal contraction also showed a statistically significant difference between the LHSA and LSP groups (13.53 ± 2.17 vs. 12.50 ± 2.03 per minute, p = 0.032). The complication rates showed no significant difference and were as follows: incidence of enterocolitis was 13.89% in the LHSA group and 20.45% in the LSP group, incidence of constipation was 11.11% after LHSA and 27.27% after LSP, and incidence of soiling was 13.89% after LHSA and 25.00% after LSP.

CONCLUSIONS

Manometric results of this study show satisfactory outcomes after LHSA. LHSA is an advanced surgical technique to make intestinal anastomosis easy and ensure a good prognosis.

Delayed appearance of mature ganglia in an infant with an atypical presentation of total colonic and small bowel aganglionosis: a case report

Background

Total colonic and small bowel aganglionosis (TCSA) occurs in less than 1% of all Hirschsprung’s disease patients. Currently, the mainstay of treatment is surgery. However, in patients with TCSA, functional outcomes are often poor. A characteristic transition zone in TCSA can be difficult to identify which may complicate surgery and may often require multiple operations.

Case presentation

We present the case of a male infant who was diagnosed with biopsy-proven total colonic aganglionosis with extensive small bowel involvement as a neonate. The patient was diverted at one month of age based on leveling biopsies at 10 cm from the Ligament of Treitz. At 7 months of age, during stoma revision for a prolapsed stoma, intra-operative peristalsis was observed in nearly the entire length of the previously aganglionic bowel, and subsequent biopsies demonstrated the appearance of mature ganglion cells in a previously aganglionic segment.

Conclusions

TCSA remains a major challenge for pediatric surgeons. Our case introduces new controversy to our understanding of aganglionosis. Our observations warrant further research into the possibility of post-natal ganglion maturation and encourage surgeons to consider a more conservative surgical approach.

Gfra1 Underexpression Causes Hirschsprung's Disease and Associated Enterocolitis in Mice

BACKGROUND & AIMS

RET, the receptor for the glial cell line-derived neurotrophic factor (GDNF) family ligands, is the most frequently mutated gene in congenital aganglionic megacolon or Hirschsprung's disease (HSCR). The leading cause of mortality in HSCR is HSCR-associated enterocolitis (HAEC), which is characterized by altered mucin composition, mucin retention, bacterial adhesion to enterocytes, and epithelial damage, although the order of these events is obscure. In mice, loss of GDNF signaling leads to a severely underdeveloped enteric nervous system and neonatally fatal kidney agenesis, thereby precluding the use of these mice for modeling postnatal HSCR and HAEC. Our aim was to generate a postnatally viable mouse model for HSCR/HAEC and analyze HAEC etiology.

METHODS

GDNF family receptor alpha-1 (GFRa1) hypomorphic mice were generated by placing a selectable marker gene in the sixth intron of the Gfra1 locus using gene targeting in mouse embryonic stem cells.

RESULTS

We report that 70%-80% reduction in GDNF co-receptor GFRa1 expression levels in mice results in HSCR and HAEC, leading to death within the first 25 postnatal days. These mice mirror the disease progression and histopathologic findings in children with untreated HSCR/HAEC.

CONCLUSIONS

In GFRa1 hypomorphic mice, HAEC proceeds from goblet cell dysplasia, with abnormal mucin production and retention, to epithelial damage. Microbial enterocyte adherence and tissue invasion are late events and therefore unlikely to be the primary cause of HAEC. These results suggest that goblet cells may be a potential target for preventative treatment and that reduced expression of GFRa1 may contribute to HSCR susceptibility.

The evolution of magnetic resonance enterography in the assessment of motility disorders in children

Gastrointestinal symptoms including constipation, diarrhoea, pain and bloating represent some of the most common clinical problems for patients. These symptoms can often be managed with cheap, widely available medication or will spontaneously resolve. However, for many patients, chronic GI symptoms persist and frequently come to dominate their lives. At one end of the spectrum there is Inflammatory Bowel Disease (IBD) with a clearly defined but expensive treatment pathway. Contrasting with this is Irritable Bowel Syndrome (IBS), likely a collection of pathologies, has a poorly standardised pathway with unsatisfactory clinical outcomes. Managing GI symptoms in adult populations is a challenge. The clinical burden of gastrointestinal disease is also prevalent in paediatric populations and perhaps even harder to treat. In this review we explore some of the recent advances in magnetic resonance imaging (MRI) to study the gastrointestinal tract. Complex in both its anatomical structure and its physiology we are likely missing key physiological markers of disease through relying on symptomatic descriptors of gut function. Using MRI we might be able to characterise previously opaque processes, such as non-propulsive contractility, that could lead to changes in how we understand even common symptoms like constipation. This review explores recent advances in the field in adult populations and examines how this safe, objective and increasingly available modality might be applied to paediatric populations.

Derivation of neural crest stem cells from human epidermal keratinocytes requires FGF-2, IGF-1, and inhibition of TGF-β1

Neural crest (NC) cells play a central role in forming the peripheral nervous system, the craniofacial skeleton, and the pigmentation of the skin during development due to their broad multilineage differentiation potential into neurons, Schwann cells, melanocytes, and mesenchymal stem cells. Recently, we identified an easily accessible source of pluripotent NC stem cells from human inter‐follicular keratinocyte (KC) cultures (KC‐NC). In this work, we examined specific conditions for the derivation of NC from KC cultures. More specifically, we examined the role of two growth factors, FGF2 and IGF1, in NC proliferation and in expression of two potent NC transcription factors, Sox10 and FoxD3. Using specific chemical inhibitors, we uncovered that the downstream regulatory pathways AKT/PI3K, MEK/ERK, and JNK/cJun may be critical in Sox10 and FoxD3 regulation in KC‐NC. The TGF‐β1 pathway was also implicated in suppressing Sox10 expression and NC proliferation. In summary, our study shed light into the role of FGF2, IGF1, and TGF‐β1 on the induction of NC from KC cultures and the pathways that regulate Sox10 and FoxD3. We also established culture conditions for sustaining KC‐NC multipotency and, therefore, the potential of these cells for regenerative medicine and cellular therapies.

Digital pathology imaging and computer-aided diagnostics as a novel tool for standardization of evaluation of aganglionic megacolon (Hirschsprung disease) histopathology

Based on a recently introduced immunohistochemical panel (Bachmann et al. 2015) for aganglionic megacolon (AM), also known as Hirschsprung disease, histopathological diagnosis, we evaluated whether the use of digital pathology and 'machine learning' could help to obtain a reliable diagnosis. Slides were obtained from 31 specimens of 27 patients immunohistochemically stained for MAP2, calretinin, S100β and GLUT1. Slides were digitized by whole slide scanning. We used a Definiens Developer Tissue Studios as software for analysis. We configured necessary parameters in combination with 'machine learning' to identify pathological aberrations. A significant difference between AM- and non-AM-affected tissues was found for calretinin (AM 0.55% vs. non-AM 1.44%) and MAP2 (AM 0.004% vs. non-AM 0.07%) staining measurements and software-based evaluations. In contrast, S100β and GLUT1 staining measurements and software-based evaluations showed no significant differences between AM- and non-AM-affected tissues. However, no difference was found in comparison of suction biopsies with resections. Applying machine learning via an ensemble voting classifier, we achieved an accuracy of 87.5% on the test set. Automated diagnosis of AM by applying digital pathology on immunohistochemical panels was successful for calretinin and MAP2, whereas S100β and GLUT1 were not effective in diagnosis. Our method suggests that software-based approaches are capable of diagnosing AM. Our future challenge will be the improvement of efficiency by reduction of the time-consuming need for large pre-labelled training data. With increasing technical improvement, especially in unsupervised training procedures, this method could be helpful in the future.

Intestinal Neuronal Dysplasia Type B: An Updated Review of a Problematic Diagnosis

Context.—

Intestinal neuronal dysplasia type B (IND B) is a controversial histopathologic phenotype that has been associated with intestinal dysmotility, either as an isolated condition or in conjunction with established pathologic disorders (eg, Hirschsprung disease). Many factors contribute to the debate over the existence and/or clinical significance of IND B, including a large body of published data based on inconsistent diagnostic criteria and methods, which have fostered many unwarranted conclusions that lack sufficient scientific basis.

Objective.—

To critically analyze existing published data regarding IND B to provide supporting evidence-based diagnostic practice and to stimulate necessary and scientifically sound research.

Data Sources.—

This update focuses on published literature related to the pathology of IND B because without a reliable pathologic diagnosis, studies of epidemiology, pathogenesis, natural history, management, and outcome are all suspect. Problems with existing data are identified explicitly with suggestions as to how future investigations should be designed and evaluated to better understand this entity.

Conclusions.—

Inconsistencies in diagnostic criteria and methods used to define IND B justifiably encumber the universal acceptance of IND B as a neuropathologic etiology for intestinal dysmotility. IND B will remain a controversial diagnosis until rigorous, well-controlled scientific studies are conducted to establish reproducible and reliable diagnostic criteria that reliably translate from one laboratory to another.

IGF2-derived miR-483-3p associated with Hirschsprung's disease by targeting FHL1

HSCR (Hirschsprung's disease) is a serious congenital defect, and the aetiology of it remains unclear. Many studies have highlighted the significant roles of intronic miRNAs and their host genes in various disease, few was mentioned in HSCR although. In this study, miR-483-3p along with its host gene IGF2 (Insulin-like growth factor 2) was found down-regulated in 60 HSCR aganglionic colon tissues compared with 60 normal controls. FHL1 (Four and a half LIM domains 1) was determined as a target gene of miR-483-3p via dual-luciferase reporter assay, and its expression was at a higher level in HSCR tissues. Here, we study cell migration and proliferation in human 293T and SH-SY5Y cell lines by performing Transwell and CCK8 assays. In conclusion, the knockdown of miR-483-3p and IGF2 both suppressed cell migration and proliferation, while the loss of FHL1 leads to opposite outcome. Furthermore, miR-483-3p mimics could rescue the negative effects on cell proliferation and migration caused by silencing IGF2, while the FHL1 siRNA may inverse the function of miR-483-3p inhibitor. This study revealed that miR-483-3p derived from IGF2 was associated with Hirschsprung's disease by targeting FHL1 and may provide a new pathway to understand the aetiology of HSCR.

Association between DSCAM polymorphisms and non-syndromic Hirschsprung disease in Chinese population

Background

Hirschsprung disease (HSCR, aganglionic megacolon) is the most frequent genetic cause of congenital intestinal obstruction. DSCAM was identified as associated to HSCR with Down Syndrome (DS-HSCR) in European population,but failed to replicate in the non-syndromic HSCR patients. We aim to further investigate the relationship of DSCAM with non-sydromic HSCR in a South Chinese cohort, the largest case-control study so far.

Method

We analyzed 1394 HSCR patients and 973 healthy controls. Two polymorphisms (rs2837770 A > G, rs8134673 A > G) on DSCAM were genotyped using Sequenom Massarray platform.

Results

Both SNPs were confirmed as associated with non-syndromic HSCR in the South Chinese population (P = 1.69E-03, OR = 1.29 for SNP rs2837770 and P = 3.00E-03, OR = 1.27 for SNP rs8134637). Of note, we demonstrated the associated SNPs were more likely to affect a subgroup of patients with short-segment aganglionosis (S-HSCR) (P = 3.06E-03,OR = 1.21 for SNP rs2837770 and P = 3.33E-03,OR = 1.21 for SNP rs8134637).

Conclusion

There is an association between DSCAM polymorphisms and non-syndromic HSCR in South Chinese population.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0637-2) contains supplementary material, which is available to authorized users.

Discovery of a First-in-Class Gut-Restricted RET Kinase Inhibitor as a Clinical Candidate for the Treatment of IBS

Abdominal pain and abnormal bowel habits represent major symptoms for irritable bowel syndrome (IBS) patients that are not adequately managed. Although the etiology of IBS is not completely understood, many of the functions of the gastrointestinal (GI) tract are regulated by the enteric nervous system (ENS). Inflammation or stress-induced expression of growth factors or cytokines may lead to hyperinnervation of visceral afferent neurons in GI tract and contribute to the pathophysiology of IBS. Rearranged during transfection (RET) is a neuronal growth factor receptor tyrosine kinase critical for the development of the ENS as exemplified by Hirschsprung patients who carry RET loss-of-function mutations and lack normal colonic innervation leading to colonic obstruction. Similarly, RET signaling in the adult ENS maintains neuronal function by contributing to synaptic formation, signal transmission, and neuronal plasticity. Inhibition of RET in the ENS represents a novel therapeutic strategy for the normalization of neuronal function and the symptoms of IBS patients. Herein, we describe our screening effort and subsequent structure-activity relationships (SARs) in optimizing potency, selectivity, and mutagenicity of the series, which led to the discovery of a first-in-class, gut-restricted RET kinase inhibitor, 2-(4-(4-ethoxy-6-oxo-1,6-dihydropyridin-3-yl)-2-fluorophenyl)-N-(5-(1,1,1-trifluoro-2-methylpropan-2-yl)isoxazol-3-yl)acetamide (15, GSK3179106), as a clinical candidate for the treatment of IBS. GSK3179106 is a potent, selective, and gut-restricted pyridone hinge binder small molecule RET kinase inhibitor with a RET IC₅₀ of 0.3 nM and is efficacious in vivo.

Large-scale replication study identified multiple independent SNPs in RET synergistically associated with Hirschsprung disease in Southern Chinese population

Hischsprung disease (HSCR) is an intestinal disorder with strong genetic components. RET was considered as the strongest contributor. Multiple single nucleotide polymorphisms (SNP) were demonstrated as associated with HSCR in different populations. However, whether the associations of reported SNPs derived from one causal variants or congregations of multiple variants were still not clear. In this study, we successfully genotyped 16 SNPs in RET with a largest case-control study to date, totaling 1470 HSCR and 1473 control subjects in South Chinese population. Multiple independent contributors were identified through pairwise and stepwise logistic regression. The intragenic synergistic effect among these SNPs were further explored and cross validated by logistic regression and multifactor dimensionality reduction (MDR). Noteworthy, in further subclinical manifestation analysis, the six potential independent contributors in RET were more essential for the patients with short-segment aganglionosis (S-HSCR). Although functional evaluations are required, our comprehensive analysis for RET gene integrating detailed disease subphenotypes might facilitate improved understanding for the genetic understanding of HSCR etiology.

Association of VAMP5 and MCC genetic polymorphisms with increased risk of Hirschsprung disease susceptibility in Southern Chinese children

Hirschsprung disease (HSCR) is a genetic disorder characterized by the absence of neural crest cells in parts of the intestine. This study aims to investigate the association of vesicle-associated membrane protein 5 (VAMP5) and mutated in colorectal cancer (MCC) genetic polymorphisms and their correlated risks with HSCR. We examined the association in four polymorphisms (rs10206961, rs1254900 and rs14242 in VAMP5, rs11241200 in MCC) and HSCR susceptibility in a Southern Chinese population composed of 1473 cases and 1469 controls. Two variants in VAMP5 were replicated as associated with HSCR. Interestingly, we clarified SNPs rs10206961 and rs1254900 in VAMP5 are more essential for patients with long-segment aganglionosis (LHSCR). Relatively high expression correlation was observed between VAMP5 and MCC using data from public database showing there may exist potential genetic interactions. SNP interaction was cross-examined by logistic regression and multifactor dimensionality reduction analysis revealing that VAMP5 rs1254900 and MCC rs11241200 were interacting significantly, thereby contributing to the risk of HSCR. The results suggest that significant associations of the rs10206961 and rs14242 in VAMP5 with an increased risk of HSCR in Southern Chinese, especially in LHSCR patients. This study provided new evidence of epistatic association of VAMP5 and MCC with increased risk of HSCR.

Association of NRG1 and AUTS2 genetic polymorphisms with Hirschsprung disease in a South Chinese population

Hirschsprung disease (HSCR) is a genetic disorder characterized by the absence of enteric ganglia. There are more than 15 genes identified as contributed to HSCR by family-based or population-based approaches. However, these findings were not fulfilled to explain the heritability of most sporadic cases. In this study, using 1470 HSCR and 1473 control subjects in South Chinese population, we replicated two variants in NRG1 (rs16879552, P = 1.05E-04 and rs7835688, P = 1.19E-07), and further clarified the two replicated SNPs were more essential for patients with short-segment aganglionosis (SHSCR) (P = 2.37E-05). We also tried to replicate the most prominent signal (rs7785360) in AUTS2, which was a potential susceptibility gene with HSCR. In our results, in terms of individual association, marginal effect was observed to affect the HSCR patients following recessive model (P = 0.089). Noteworthy, significant intergenic synergistic effect between rs16879552 (NRG1) and rs7785360 (AUTS2) was identified through cross-validation by logistic regression (P = 2.45E-03, OR = 1.53) and multifactor dimensionality reduction (MDR, P < 0.0001, OR = 1.77). Significant correlation was observed between expression of these two genes in the normal segments of the colons (P = 0.018), together with differential expression of these genes between aganglionic colonic segments and normal colonic segments of the HSCR patients (P value for AUTS2 <0.0001, P value for NRG1 = 0.0243). Although functional evaluation is required, we supply new evidence for the NRG1 to HSCR and raised up a new susceptibility gene AUTS2 to a specific symptom for the disease.

A 6-year retrospective review of histopathological pattern of surgical biopsies in children with refractory constipation in a Tertiary Hospital in Ghana

BACKGROUND

Children with chronic constipation dating to infancy frequently undergo rectal biopsy in order to rule out Hirschsprung's disease (HD) which is a common cause of this sort of presentation. Few publications have however focused on the documentation of the proportion of such patients who truly had histopathological findings confirming the disease. In this preliminary work, we aim to present the histopathological findings of children who had rectal biopsies in our centre from 2009 to 2014.

PATIENTS AND METHODS

A retrospective study was undertaken to review the histopathology reports of all rectal biopsies submitted to the Department of Pathology of the Komfo Anokye Teaching Hospital, Kumasi, from 2009 to 2014 on account of refractory constipation and suspected HD. Patient's biodata, clinical signs and symptoms were extracted from the request form.

RESULTS

Eighty-eight cases were seen during the study period with male to female ratio 2.8:1 and age range 6 months to 10 years. The modal age range is 24-36 months. Seventy-six of the specimens were adequate for histopathological assessment with 64 cases confirmed as HD while 12 cases were normal. Out of the confirmed cases, 3 cases showed absence of ganglion cells but no hypertrophy of nerve fibres.

CONCLUSION

This preliminary work reveals that HD is rarely confirmed by biopsy in early infancy in our setting due to late presentation although the epidemiology of the disease is similar to that reported elsewhere.